Clamp fixture for water-cooled induction coil



Dec. 30, 1958 L. c. MILLER 2,366,330

CLAMP FIXTURE FOR WATER-COOLED INDUCTION con.

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CLAMP FIXTURE FOR WATER-COOLED INDUCTION COIL Filed March 21, 1957 3Sheets-Sheet 2 fie. c2

Dec. 30, 1958 L. c. MILLER 2,866,880

CLAMP FIXTURE FOR WATER-COOLED INDUCTION COIL Filed March 21, 1957 HG.Q.

3 Sheets-Sheet 3 1'33 F aci INVENTOR, (EON/0%" C. Mlllfe United StatesPatent CLAMP FIXTURE FOR WATER-COOLED INDUCTION COIL Leonidas C. Miller,Los Angeles, aiif.

Application March 21, 1957, Serial No. 647,686

20 Claims. (Cl. 219-1049) This invention relates to induction heatingapparatus and is particularly directed to improvements in supporting awater-cooled induction coil.

Induction heating machines are commonly provided with electricalterminal blocks for delivery of high frequency electrical energy to aninduction heating coil. It is an important object of my invention toprovide an improved form of clamp fixture to be mounted on the terminalblocks of such induction heating machine and to provide a novel meansfor releasably supporting the induction heating coil.

Induction heating coils are generally formed of metal tubing so thatthey may readily be water-cooled. It is important that the water orother coolant be continuously circulated through the coil whenever thecoil is electrically energized, in order to prevent damage to the coilby overheating. Accordingly, it is another feature of my invention toprovide a novel clamping apparatus which not only supports the inductingheating coil with proper electrical contact but also provides thenecessary connections for circulating a coolant through the turns of thecoil.

Another object is to provide a clamp fixture for a watercooled inductioncoil having optimum electrical characteristics.

Another object is to provide a device of this type havingvalve-controlled coolant passageways provided in the support fixture.

Another object is to provide a device of this type in which valvescontrolling the flow of coolant are actuated by the same member whichclamps the induction coil asssembly relative to the fixture.

Another object is to provide a device of this type which permits theinduction coil assembly to be mounted on the fixture in either uprightor inverted position.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

Figure 1 is a perspective view showing a preferred embodiment of thisinvention.

Figure 2 is a sectional elevation thereof taken substantially along thelines 22 as shown in Figure 1.

Figure 3 is a transverse sectional elevation taken substantially on thelines 33 as shown in Figure 2.

Figure 4 is a fragmentary view similar to a portion of Figure 2, showinga shut-off valve in open position.

Figure 5 is a sectional plan view of induction heating coil assembly,taken substantially on the lines 5--5 as shown in Figure 2.

Figure 6 is a side elevation partly in section, showing a modified formof this invention.

Figure 7 is a sectional elevation taken substantially on the lines 7-7as shown in Figure 6.

Figure 8 is a sectional elevation taken substantially on the lines 88 asshown'in Figure 7.

Figure 9 is a sectional plan view taken substantially on the lines 9--9as shown in Figure 6. 7

Referring to the drawings, the clamp fixture generally "ice designated10 includes a metallic body 11 which comprises a pair of metallic bodysections 12 and 13 mounted in parallel 'back-to-back relationship andseparated by relatively thin insulator 14. Each of the body sections isprovided with a mounting flange 15 at one end having apertures 16. Asshown in Figure 2, threaded elements 17 extend through these aperturesand act to secure the flanges 15 in supporting contact with theterminals 18 of an induction heating machine, not shown.

Insulator straps 19 and 20 are fixed to the ends of the body sections 12and 13 remote from the apertured flanges 15. A crossbar 21, alsohereinafter referred to as a first member, extends horizontally betweenthe upper ends of the insulator straps Hand 20. This-crossbar is made ofmetal and is provided with a central threaded opening 22 for receptionof the axial screw 23. The ends of the crossbar 21 are recessed into theinsulator straps 19 and 20, as shown at 24. Threaded fastenings 25 holdthe parts in position. A second crossbar 26 stands horizontally betweenthe lower ends of the insulator straps 19 and 2t) and is held inposition by means of the recesses 27 and threaded fastenings 23. Thiscrossbar 26, hereinafterreferred to as a second member, is formed ofelectrically insulating material and is provided with a central groove29 in the vicinity'of the insulating separator 14. Machine'screws 3t)secure the strap 19 to the body section 12 and, similarly, machinescrews 31 secure the strap 2% to the body section 13. The lower crossbar26 is thus maintained in contact with the lower surfaces of the bodysections 12 and 13.

A slide block 33 formed of an insulating material is guided forlongitudinal sliding movement between the straps 19 and 2t) and moves ina direction toward and away from body sections 12 and 13. Oppositelyextending horizontal pins 34 and 35 are fixed on the block 33 and travelin vertical guide slots 36 and 37, respectively, provided in the straps19 and 20. The lower end of the screw 23 is connected to the block 33and the upper end is provided with a handwheel 38. The connectionbetween 'thescrew 23 and the block 33 includes a ball bearing 39 mountedin the lower end of the central bore 40 in the block 33. The extremelower end of the screw 23 is recessed to rest on the ball bearing 39. Agroove 41 in the screw 23 receives a retaining pin 42 fixed on the block33. From this description, it will be understood that the turning of thescrew 23 by means of the handwheel 38 serves to raise and lower theclamping block 33 with respect to the body 11.

An induction coil assembly, generally designated 45, includes a coil 46,having several turns and preferably formed of copper tubing which issquare in cross-section. Laterally spaced parallel metallic bars 47 and48 are connected to end portions 49 and 50a, respectively, of the coil46. The bars 47 and 48 comprise terminal pads and the upper and lowercontact surfaces thereof, 50 and 51, lie in parallel planes. The barsand the terminal pads 47 and 48 are separated by an air gap 52 and aremaintained in their laterally spaced relationship by means of a spacer53 formed of insulation material and connected to the bars by means offastenings 54.

The ends of the parallel bars 47 and 48 remote from the coil 46, areadapted to be received within a clamping space 55 defined between theupright straps 19 and 20 and between the block 33 and the upper surfaces56 and 57 of the body sections 12 and 13. The spacer 53 extendslaterally beyond the edges of the bars 47 and 48 to form an abutmentengaging the straps 19 and 20 to limit movement of the terminal padsinto'the clamping space '55. The lower surface of the terminal pad 47 isheld in surface-contact with the upper surface 560i the body section 12.Similarly, the lower surface of the aseasso body section 12, terminalpad 47, coil 46, terminalpad 48, body section 13 and back to the otherapertured flange 15. An insulated spacer block 60 may be secured to thebody sections 12 and 13 by means of threaded fastening 61 and the spacerblock assists in maintaining the insulator 14 in clamped positionbetween the body sections 12 and 13.

v The induction coil assembly 45 may be removed from the clamp fixtureby turning the handwheel 38 in the direction to raise the block 33 awayfrom the body 11. Induction coilassembly may then be withdrawn forwardlyout of the clamping space 55. If desired, it may be inverted and thenreinserted into the clamping space so that the coil 46 is placed in adifferent position with respect to the body 11.

In order to prevent damage to the coil 46 by overheating, it isessential to circulate a coolant through the interior of the tubeforming the coil. This is accomplished by providing passages and 66which extend within the bars 47 and 48, respectively, and by providingports which establish communication between the passage 65 and the end49 of the coil tube and between the passage 66 and the end 50 of thetube. The ends of the passages 65 and 66 are closed by plugs 67 and 68.Ports 69 extend through the upper and lower contact surfaces of the baror terminal pad 47 and communicate with the passage 65. Similarly, ports70 extend through the upper and lower contact surfaces of the bar orterminal ,pad 48 and communicate with the passage 66.

The port 70 is adapted to be aligned with opening 71 provided in thebody section 13 and extend to its upper surface 57. Port 70 is adaptedfor alignment with opening 72 formed in the body section 12. Seal rings73 are provided on the body sections adjacent the surfaces 56 and 57 andencircling the openings 71 and 72. Similar seal rings 74 are mounted ininsert pieces 75 provided on the block 33. The seal rings 73 and 74engage the contact surfaces 50 and 51 of the terminal pad 47 and 48 toprevent leakage.

A passageway is provided in each of the body sections 12 and 13. Thepassageway 77 communicates with the opening 72 in the body section 12.Similarly, the passageway 78 communicates with the opening 71 in thebody section 13. The passageways 77, and 78 are substantially identicaland each is provided with a shut-off valve assembly 79 interposedbetween the ends thereof. A stationary downwardly facing seat 80 isprovided on each body section and a movable valve 81 is adapted to closeagainst the seat. A spring 82 urges the valve element 81 toward closedposition against the seat 80 and a toggle lever 83 having a cam surface84 acts on the valve stem to move the element 81 away from the seat 80.When the toggle lever 83 is in the position shown in Figure 2, the valveis closed, and when the lever is in the position shown in Figure 4, thevalve is open. The passageways 77 and 78 extend through the aperturedflanges 15 and are aligned with coolant openings 86 provided in theterminals 18 of the induction heating machine. Seal rings 87 areprovided to prevent leakage. When the valves 79 are opened, a coolantsuch as water is circulated through the passageways in the body sectionsand through the terminal pads and coil on the induction heating coilassembly 45.

When it is desired to remove the assembly 45 from the fixture 10, thetoggle levers 83 are manually actuated to close the valves 79 and thehandwheel 38 is then turned to raise the block 33. The induction coilassembly 45 may then be withdrawn forwardly from the clamping spacebeneath the block 33. Some small leakage of coolant from the passages inthe terminal blocks 47 and 48 and from, the interior of the coil 46 mayoccur, but

otherwise the coolant pressure system is shut off by the valves 79 sothat no major amount of leakage occurs from the fixture 10. It will beobserved that the seal rings 74 in the block 33 and the seal ring 73 inthe body sections 12 and 13 prevent leakage of coolant when the terminalbars 47 and 48 are clamped in position, and this is true whether thecoil assembly 45 is clamped in upright or inverted position.

In the modified form of my invention, shown in Figures 6-9, inclusive,the induction coil assembly 45 is identi cal to that previouslydescribed. The clamp fixture 10a is mounted on the terminals 18 of theinduction heating machine in the same manner as described above, but theshut-off valves are actuated by the screw 23a and handwheel 38a insteadof beingmanually actuated. The insulator straps 19a and 20a are slidablymounted on the body sections 12a and 13a by means of guide caps 90 and91 fixed in place by threaded fastenings 92. Limit stops in the form ofpins 93 engage shoulders 94 to limit downward movement of the straps 19aand 20a with respect to the body sections.

In this form of my invention, a valve assembly is provided at theforward end of each of the body sections 12a and 13a. Since the valveassemblies are duplicates and function in the same manner, only one needbe described. A vertical bore 101 in the body section 13a receives astationary sleeve 102 which is fixed into position by means of a plug103 having a projection 104. The upper end of this stationary sleeve 102is provided with a valve seat 105. A movable valve element 106 closesagainst this seat and is carried on a valve stem 107 slidably mountedwithin the bore 108 of the sleeve 102. A lateral port 109 in the sleeve102 communicates with the passageway 78a provided in the body section13a. The valve element 106 is closed against the seat by means of thespring 110.

A collar 112 is slidably received within the bore 113 of a skirt 114provided on the stationary sleeve 102. The collar 112 has a bore 115which slidably receives the valve stem 107. A compression spring 116acts on the collar 112 to maintain it in contact with the crossbar 26awhich is formed of insulation material and which connects the lower endsof the straps 19a and 20a. When the terminal pads 47a and 48a of theinduction coil assembly 45 are clamped in position between the block 33aand the upper surfaces of the body sections 12a and 13a, the parts arein the positions shown in Figures 6 and 7 of the drawings. The lowerends of thevalve stems 107 engage the crossbar 26a, thereby lifting thevalve elements 106 away from the seats 105, permitting flow of coolant.When it is desired to remove the induction coil assembly 45 from theclamp fixture 10a, the handwheel 38a is manually actuated to turn thescrew 23a. The force of the springs 116 acting through collars 112against the crossbar 26a causes the straps 19a and 20a to move downwardwith respect to the body sections 12a and 13a as the screw 23a isturned. Continued turning movement of the screw 23a brings the parts tothe position shown in Figure 8, with the valve elements 106 closedagainst the seats 105. Further turning movement of the screw 23a bringsthe limit stops 93 into engagement with the shoulder 94 and thereafterraises the block 33a away from the body sections 12a and 13a to permitWithdrawal of the induction coil assembly 45. Conversely, turning of thehandwheel 38 in a direction to clamp the induction coil 45 in positionserves first to clamp the terminal pads 47a and 48a and thensubsequently opens the valves to permit coolant to flow. This is asafety feature since it avoids overheating of the induction coilassembly 45 by inadvertent failure to open the coolant valves prior toenergizing the coil electrically.

Having fully described my invention, it is to be understood that} do notwish to belimited to the details set forth, but my invention is of thefull scope of the appended claims.

I claim: a

1. In a device of the class described, the combination of: a metallicbody comprising a pair of spaced parallel body sections, means on thebody whereby it may be connected to a support, a member fixed relativeto the body and provided with an opening, an axial screw extendingthrough the opening, a block guided for movement relative to the bodyand engaged by the screw, an induction coil assembly provided withlaterally spaced parallel terminal pads having co-planar contactsurfaces, each terminal pad being adapted to have surface contact withone of said body sections, respectively, whereby the terminal pads mayboth be. removably clamped between the body sections and said block bymeans of said screw.

2. Apparatus set forth in claim 1 in which the terminal pads each haveparallel surfaces to permit the induction coil assembly to be invertedwith respect to the metallic body.

3. Apparatus set forth in claim 1 wherein coolant passages are providedin the body sections and con: nected with coolant passageways providedin the terminal pads.

4. In a device of the class described, thecombination of: a metallicbody comprising a pair ,of spaced parallel body sections; means at oneend of each body section whereby it may be releasably connected to asupport, parallel straps at the other end of the body, one secured toeach body section, a member extending between projecting ends of thestraps and provided with an opening, an axial screw extending throughthe opening, a block guided for movement between the straps and engagedby the screw, an induction coil assembly provided with laterally spacedparallel terminal pads having coplanar contact surfaces, the terminalpads being insertable into a space defined between the straps with acontact surface of each terminal pad in surface contact with one of saidbody sections, respectively, whereby the terminal pads may both beremovably clamped between the body sections and said block by means ofsaid screw.

57 Apparatus set forth in claim 4 in which the terminal pads each haveparallel surfaces to permit the induction coil assembly to be invertedwith respect to the metallic body.

6. Apparatus set forth in claim 4 wherein coolant passages are providedin the body sections and connected with coolant passageways provided inthe terminal pads.

7. In a device of the class described, the, combination of: a metallicbody comprising a pair of parallel body sections having an insulatorelement clamped therebetween, mounting means at one end of each bodysection whereby it may be releasably connected to a terminal of aninduction heating machine, parallel insulator straps at the other end ofthe body, one secured to each body section, a member extending betweenprojecting ends of the straps and provided with a threaded opening, anaxial screw engaging within the threaded opening, a block guided formovement between the straps and engaged by the screw, an induction coilassembly provided with laterally spaced parallel terminal pads, a spacerelement extending between the terminal pads, the terminal pads beinginsertable into a space defined between the straps with each terminalpad in surface contact with one of said body sections, respectively,whereby the terminal pads may be removably clamped between the bodysections and said block by means of said screw, the spacer elementforming an abutment to limit movement of the terminal pads into saidspace.

8. Apparatus set forth in claim 7 in which the terminal pads each haveparallel surfaces to permit the induction coil assembly to be invertedwith respect to the metallic body.

9. Apparatus set forth in claim 1 wherein coolant passages are providedin the body sections and connected with coolant passageways provided inthe terminal pads.

10. In a device of the class described, the combination of: a metallicbody comprising a pair of spaced parallel body sections, support meansat one end of each body section whereby it may be connected to one ofthe terminals of an induction heating machine, a block guided forlongitudinal movement toward and away from the body sections, aninduction coil assembly including a pair of laterally spaced parallelmetallic bars comprising terminal pads, the terminal pads being adaptedto be removably clamped between the body sections of said block ineither of two positions apart, each metallic bar having a coolantpassageway therein and communicating ports extending to opposed surfacesof the terminal pads, each body section having a coolant passageway threin and a communicating opening extending to a surface thereof, andseal means on the block and on the body sections adapted to preventleakage adjacent the ports in either position of the terminal pads.

11. In a device of the class described, the combination of: a metallicbody comprising a pair of spaced parallel body sections, support meansat one end of each body section whereby it may be connected to one ofthe terminals of an induction heating machine, a block guided forlongitudinal movement toward and away from the body sections, aninduction coil assembly including a pair of laterally spaced parallelmetallic bars comprising terminal pads, the terminal pads havingparallel contact surfaces lying in parallel planes, so thatthe inductioncoil assembly is adapted to be removably clamped between the uppersurfaces of the body sections and said block in either upright orinverted positions, each metallic bar having a coolant passagewaytherein and communicating ports extending to said opposed contactsurfaces of the terminal pads, each body section having a coolantpassageway therein and a communicating opening extending to the uppersurface thereof, and seal means on the block and on the body sectionsadapted to prevent leakage adjacent the ports in either position oftheinduction coil assembly.

12. In a clamp device adapted to be secured to the terminals of aninduction heating machine and adapted to support an induction coilassembly, the combination of: a metallic body comprising a pair oflaterally spaced parallel body sections, support means at one end ofeach body section whereby it may be connected to one of the terminals ofthe induction heating machine, parallel insulator straps at the otherend of each body section, one secured to each body section, a firstmember extending between projecting ends of the straps above the bodysections andprovided with a threaded opening, an axial screw engagingwithin the threaded opening, a block guided for longitudinal movementbetween the straps and engaged by the screw, a second member extendingbetween the straps below the body sections, the straps, block and uppersurfaces of the body sections defining a clamping space for reception ofone end of an induction coil assembly.

13. In a clamp device adapted to be secured to the terminals of aninduction heating machine and adapted to support an induction coilassembly, the combination of: a metallic body comprising a pair oflaterally spaced parallel body sections, support means at one end ofeach body section whereby it may be connected to one of the terminals ofthe induction heating machine, parallel insulator straps at the otherend of each body section, one secured to each body section, a firstmember extending between projecting ends of the straps above the bodysections and provided with a threaded opening, an axial screw engagingwithin the threaded opening, a block guided for longitudinal movementbetween the straps and engaged by the screw, a second member extendingbetween the straps below the body sections,

the straps, block and upper surfaces of the body sections defining aclamping space for reception of one end of an induction coil assembly,and coolant passage means on each body section communicating with saidclamping space.

14. In a coil assembly clamp device adapted to b secured to theterminals of an induction heating machine and adapted to support aninduction coil assembly, the combination of: a metallic body comprisinga pair of spaced parallel body sections, support means at one end ofeach body section whereby it may be connected to one of said terminals,a block guided for longitudinal movement toward and away from said bodysections, the block and upper surfaces of the body sections defining aclamping space for reception of one end of an induction coil assembly,each body section having an opening communicating with said clampingspace, and each body section having a coolant passage extending from theflange to said opening.

15.,In a coil assembly clamp device adapted to be secured to theterminals of an induction heating machine and adapted to support aninduction coil assembly, the combination of: a metallic body comprisinga pair of spaced parallel body sections, support means at one end ofeach body section whereby it may be connected to one of said terminals,a block guided for longitudinal movement toward and away from said bodysections, the block and upper surfaces of the body sections defining aclamping space for reception of one end of an induction coil assembly,each body section having an opening communicating with said clampingspace, and each body section having a coolant passage extending from theflange to said opening, and a manually operable shut-off valve on eachbody section interposed in its respective coolant passage.

16. In an induction coil assembly, the combination of: a pair oflaterally spaced parallel metallic bars comprising terminal pads, theterminal pads having contact surfaces lying in the same plane, a coilhaving at least one turn and formed from a tube, each end of the tubebeing joined to an end of one of the metallic bars, respectively, eachbar having a coolant passage extending longitudinally thereof andcommunicating with its respective tube end, and each bar having alateral port communicating with its coolant passage and extendingthrough its respective contact surface.

17. In an induction coil assembly, the combination of: a pair oflaterally spaced parallel metallic bars comprising terminal pads, theterminal pad each having parallel contact surfaces, each contact surfaceon one pad passage extending longitudinally thereof and communieatingwith its respective tube end, and each bar having a lateral portcommunicating with its coolant passage and extending through at leastone of said parallel contact surfaces.

18. In an induction coil assembly, the combination of: a pair oflaterally spaced parallel metallic bars comprising terminal pads, theterminal pads being rectangular in cross-section and each havingparallel contact surfaces, each contact surface on one pad beingco-planar with a contact surface on the other pad a coil having at leastone turn and formed from a tube each end of the tube being joined to anend of one of the metallic bars, respectively, each bar having a coolantpassage extending longitudinally thereof and communicating with itsrespective tube end, and each terminal pad having oppositely extendinglateral ports communicating with its coolant passage and extendingthrough both of its respective contact surfaces.

19. In a device of the class described, the combination of: a metallicbody comprising a pair of spaced parallel body sections, a block guidedfor longitudinal sliding movement relative to the body sections, aninduction coil assembly having laterally spaced portions clamped betweenthe block and the body sections, each body section having a coolantpassageway communicating with a coolant passage in the induction coilassembly, a shut-off valve assembly on each of the body sectionscontrolling flow through each of said passageways, each valve assemblyhaving a movable valve element, and common means for moving the blockand said valve elements in order to clamp the induction coil assembly inplace and to open the valve assemblies.

20. In a device of the class described, the combination of: a metallicbody comprising a pair of spaced parallel body sections, parallelinsulator straps slidably mounted on the body sections, a first memberextending between projecting ends of the straps above the body sectionsand provided with a threaded opening, an axial screw engaging within thethreaded opening, a block guided for longitudinal movement between thestraps and engaged by the screw, 21 second member extending between thestraps below the body sections, the straps, block and upper surfaces ofthe body sections defining a clamping space, an induction coil assemblyhaving laterally spaced portions projecting into the clamping space,each body section having a coolant passageway communicating with acoolant passage in the induction coil assembly, a shut-off valveassembly on each of the body sections controlling flow through each ofsaid passageways, each valve assembly having a movable valve elementactuated by said second member, whereby turning of the screw serves toclamp the induction coil assembly in place and to open the valveassemblies.

References Cited in the file of this patent FOREIGN PATENTS 854,552Germany Nov. 6, 1952

